SAN CRISTOBAL, Venezuela (AP) — Ambulance drivers in Venezuela say they're unable to fuel up and speed away to emergencies as gasoline shortages deepen.

Jaiberth Zambrano of Civil Protection services in Tachira state said this week that officials overseeing filling stations started turning away ambulances. Drivers were previously able to jump to the front of mile-long gas lines.

Despite having the world's largest petroleum reserves, Venezuela is in the throes of a historic political and economic crisis that has caused severe gas scarcities.

Luis Vicente León of Caracas-based polling firm Datanalisis says that ambulances are likely being edged out in a corrupt system run by smugglers who sneak Venezuela's dirt-cheap gas to Colombia for huge profits.

Political coordinator Rodolfo Suárez denied claims Thursday that ambulances didn't have enough gas and blamed U.S. sanctions for shortages.